(1) Field of the Invention
The invention relates to the fabrication of integrated circuit devices, and more particularly, to an apparatus to quantify the adhesion of overlying films such as dielectrics and conductors deposited on a semiconductor surface, such as the surface of a substrate.
(2) Description of the Prior Art
In the fabrication of integrated circuits, the integration of films such as dielectrics and conductors into the circuit presents a challenge. One important aspect of this integration relates to the adhesion of films (such as a film of a dielectric or a film of a conductive material) that are deposited over semiconductor surfaces such as the surface of a semiconductor substrate. In the microelectronics industry, a simple tape test, documented by the American Society for Testing and Materials (ASTM) under D3359, is typically performed to evaluate qualitatively the adhesion of a dielectric to an underlying surface. The test method teaches the placement of an adhesive tape over an area of the film, wherein the area contains a set of incisions. This is followed by the removal of the adhesive tape away from the area by seizing the free end of the tape and pulling the tape rapidly back upon itself under an angle that is as close as possible to an angle of 180 degrees.
However, this test method has several drawbacks:
(1) the test method does not provide a quantitative measurement of the adhesion between the film and the underlying surface,
(2) no standards are ascribed to the several parameters that are used in this method of testing, such as the speed of pulling (removing) the tape, the type of adhesive tape that is used for the test, the pressure of rubbing the adhesive tape to the surface of the film and the force applied during the creation of the incisions in the film,
(3) inconsistencies are introduced during the test, typically due to the influence of the human factor, particularly to the personality and disposition of the person that is performing the test.
The present invention therefore provides a method to quantitatively measure the adhesion of films and provides an apparatus for measuring and quantifying the adhesion between a deposited film and an underlying surface.
U.S. Pat. No. 5,310,442(Ametani) shows an apparatus for removing adhesive tape from semiconductor wafer surfaces. However, this reference differs from the apparatus of the invention.
U.S. Pat. No. 6,002,259(Griffin, Jr. et al.) teaches an electrostatic adhesion tester for thin film conductors.
U.S. Pat. No. 5,121,706(Nichols et al.) shows an apparatus for applying a composite insulating coating to a substrate. The patent discloses the D3359-83 ASTM test. Nichols et al. show an apparatus for applying coatings to substrates.
A principal objective of the invention is to provide a method and apparatus for quantifying adhesion between a deposited film, such as a film of a dielectric or a film of a conductive material, and an underlying surface.
Another objective of the invention is to provide standard measurement parameters for the measuring of the adhesion between a deposited semiconductor film of material and the underlying surface.
Yet another objective of the invention is to remove inconsistencies in quantifying adhesion between a deposited film of semiconductor material and an underlying surface.
In accordance with the objectives of the invention a new apparatus is provided for the quantification of the adhesion of a film over a substrate. In particular, the peeling force and the rate of peeling are quantified by providing a first means for measuring the peeling force, a second means for measuring the rate of peeling, a third means for securing a piece of wafer, an adhesive tape, a tape holder and a resilient, flexible component.